ROS Technologies, Inc, is a medical diagnostics company developing a blood test to predict sudden death risk in patients with heart failure (HF). Heart failure affects more than five million Americans and increases the risk of sudden death. This application sets out to develop a simple, inexpensive blood test to help predict sudden death risk that may prevent unnecessary ICD implants and help screen moderate risk populations now not treated. One advantage of this test is that it reflects the state of cardiac Na+ channels (SCN5a). Modulation of these channels is already known to cause arrhythmias such as Brugada Syndrome when too little current is present and Long QT syndrome when too much current is present. Recently, we reported three SCN5a mRNA alternative splicing variants are upregulated in human HF tissue. These variants encoded nonfunctional cardiac Na+ channels. Our preliminary data show that white blood cells (WBCs) have abnormal Na+ channel mRNA splicing, that WBC splicing is highly correlated with that in heart, and that HF patients have reduced full length Na+ channel and increased variants in their heart and blood when compared to control patients. Hypothesis. Since SCN5A is the main channel generating current for electrical propagation in heart muscle and mutations in this channel are known to cause arrhythmic sudden death, we hypothesize that these truncated mRNAs for the Na+ channel will contribute to arrhythmic risk in HF, and by quantifying their presence in blood, it will be possibl to develop a blood test that would help predict sudden death risk in HF patients. Product. This phase I application will establish the feasibility of a proprietary blood test to predict arrhythmi risk in HF patients. If successful, this test would be unique, since no other blood tests exist for this purpose. Specific aim 1: To determine if altered WBC Na+ channel mRNA variant abundances are associated with an elevated likelihood of sudden death risk as measured by appropriate discharge in patients with ICDs. Plans for Phase II. Phase II would be a prospective, multisite examination of the same relationship and product prototype development. Commercial Application. Initially, ROS' novel blood test will be sought by hospitals (5,000 in the US) and physicians for use in over 500,000 patients who are diagnosed with HF annually in order to prevent unnecessary ICD implants. A reduction in the number of ICD implantations would save ~$150 million annually in the US healthcare system. PUBLIC HEALTH RELEVANCE: ROS Technologies, Inc. is a medical diagnostics company developing a blood test to predict sudden death risk in patients with heart failure. Heart failure occurs in more than 550,000 US citizens each year, but there are no simple, reliable ways of predicting who is at highest risk for sudden cardiac death and who will benefit from an implanted defibrillator. This Phase I STTR application sets out to establish the feasibility of a blood test o predict sudden death risk and thereby help direct more than $1 billion/year in medical expenses to those most likely to benefit.